The invention relates to a method and apparatus of epitaxial deposition.
In order to manufacture epitaxially deposited semi-conductor layers on semi-conductor substrate discs, various methods are known. In preferred manner these layers are manufactured by decomposing a reaction gas made up of a semi-conductor compound by means of the semi-conductor discs which are to be coated, whereby monocrystalline semi-conductor material is deposited on the substrate discs. In a known method both source material and the semi-conductor discs to be coated are housed in an evacuated reaction vessel. Thus the substrate discs and the source material are arranged at the remote ends of an elongate tube. The source material and the substrate discs are brought to different temperatures. Then a syringe, containing iodine, for example, is opened inside the reaction vessel so that a partial pressure equilibrium of gaseous and chemical semi-conductor compounds may be formed in the region of the source discs and in the region of the semi-conductor substrate discs. Because of the temperature difference between the two equilibrium systems they come into reciprocal action whereby semi-conductor material is worn away from the source discs and by conversion of the reaction gas in the region of the semi-conductor substrate discs is deposited again. This method is very expensive at the moment since the reaction vessel has to be evacuated and sealed for each epitaxial process. Furthermore, in this method special auxiliary devices are necessary in the sealed system in order to release the reaction gas.